vector底层实现（源码）

#pragma once

#include<assert.h>

namespace bit

{

template<class T>

class vector

{

public:

typedef T* iterator;

typedef const T* const_iterator;

iterator begin()

{

return _start;

}

iterator end()

{

return _finish;

}

const_iterator begin() const

{

return _start;

}

const_iterator end() const

{

return _finish;

}

vector()

{}

// v2(v1)

vector(const vector<T>& v)

{

reserve(v.capacity());

for (auto& e : v)

{

push_back(e);

}

}

// vector<int> v1 = { 1,2,3,4,5,6,7,8,9,10 };

vector(initializer_list<T> il)

{

reserve(il.size());

for (auto& e : il)

{

push_back(e);

}

}

// 类模板的成员函数可以是函数模板

template <class InputIterator>

vector(InputIterator first, InputIterator last)

{

while (first != last)

{

push_back(*first);

++first;

}

}

vector(size_t n, const T& val = T())

{

reserve(n);

for (size_t i = 0; i < n; i++)

{

push_back(val);

}

}

vector(int n, const T& val = T())

{

reserve(n);

for (int i = 0; i < n; i++)

{

push_back(val);

}

}

void swap(vector<T>& v)

{

std::swap(_start, v._start);

std::swap(_finish, v._finish);

std::swap(_endofstorage, v._endofstorage);

}

// v1 = v3

vector<T>& operator=(vector<T> v)

{

swap(v);

return *this;

}

~vector()

{

delete[] _start;

_start = _finish = _endofstorage = nullptr;

}

size_t size() const

{

return _finish - _start;

}

T& operator[](size_t pos)